A pleurodontan iguanian from the Green River Formation (Eocene) is described in detail and named. The new taxon is known only from a single specimen preserving all areas of the body. Although many of the bone surfaces are eroded, almost all of the skeleton is present and some cartilaginous elements are preserved. The new taxon shares important characteristics with the extant anisolepines and leiosaurines, including the morphology and placement of the caudal autotomy planes, the postxiphisternal inscriptional ribs, and notched or fenestrated clavicles that are expanded proximally. This is the earliest complete iguanian known from the Americas and the earliest known iguanian that may be confidently referred to an extant “family.” A phylogenetic analysis including this taxon and other fossil and extant iguanians offers some support for the monophyly of Polychrotidae sensu lato, Tropiduridae sensu lato, and non-acrodont iguanians (Pleurodonta).

A comparative analysis of the postcranial skeletal morphology of three species of pakicetid cetaceans provides new insights into their locomotor behavior. in gross morphology, they are similar to their smaller early artiodactyl relatives, lacking obvious signs of their transition to an aquatic niche. Features linking them are related to a cursorial adaptation centered in the reduction of joint mobility to the parasagittal plane, evident in both the elbow and the ankle. in addition to cursorial features of the limbs, the earliest whales and early artiodactyls both possess a long, stable lumbus and robust tails. the three pakicetid genera can be distinguished by size, proportion, and details of articular morphology. However, all pakicetid postcrania bear microstructural specializations commensurate with aquatic locomotion, and incompatible with cursoriality. the most striking modification is the presence of systemic increased bone density, likely used as skeletal ballast. When both postcranial morphology and microstructure are considered, it can be concluded that pakicetid cetaceans were highly adapted for an aquatic niche. As in several extant semiaquatic taxa, the pakicetid tail undoubtedly contributed to its locomotor repertoire, whether in propulsion or stabilization.

We establish a new genus of a hyaenaelurine hyaenodontid (Creodonta: Mammalia), Orienspterodon for “Pterodon” dahkoensis, which is known from three late middle Eocene localities in central and southern China and Myanmar. This paper provides a full description of the species and a comment on the early evolution of Hyaenaelurinae. Some features of Orienspterodon (p2–p3 without an anterior accessory cuspulid, lesser reduction of the m3 talonid relative to m1–m2 talonids, double-rooted P3, and better fusion of the paracone and metacone on M1) confirm that O. dahkoensis is distinct from Pterodon. Orienspterodon differs from the other specialized hyaenodontids from the Paleogene of Asia in being a hyaenaelurine, in being unrelated to Hyaenodon, and in having a geographical distribution in the southern part of the continent. Orienspterodon represents the earliest fossil records of Hyaenaelurinae, and some features (small metaconid on m3, basined talonid on all lower molars, a short and more diagonally oriented metastyle, large size, better fused paracone and metacone) indicate an early branching of this genus from the other hyaenaelurines.

The Kanosh Formation of the Great Basin of western North America contains the oldest abundant and moderately diverse bryozoan fauna known from North America. Six species are here described from this formation at Ibex in the Confusion Range, Utah. They comprise three species of esthonioporine stenolaemates and three trepostomes. Two new genera (Ibexella and Kanoshopora) and three new species (I. multidiaphragmata, K. droserae, and Eridotrypa hindsi) are introduced. The endozone of Kanoshopora n. gen. is very unusual among bryozoans in being filled with vesicles that are divided by beaded walls into longitudinal files close to the boundary with the exozone.

The enigmatic Silurian fossil Bunodella horrida Matthew, 1889 was originally described as a crustacean (Matthew, 1889). B. horrida was later included with the pseudoniscid synziphosurines by Størmer (1955) in the Treatise on Invertebrate Paleontology. Bunodella Matthew, 1889 was subsequently dismissed as a merostome in later treatments (Eldredge, 1974; Anderson and Selden, 1997). However, the type and only known specimen (Fig. 1), housed in the New Brunswick Museum (NBMG), has not been re-studied since Matthew's initial description. Reexamination of this fossil has led us to interpret it as the partial coxa of a pterygotid eurypterid swimming leg. The coxa is likely to belong to Acutiramus Ruedemann, 1935 rather than any other pterygotid, but it cannot be further separated from other species in the genus and is left as Acutiramus sp. A more precise assignment must await more diagnostic material (e.g., chelicerae). The genus Bunodella Matthew, 1889 is therefore deemed invalid and its usage discontinued. Bunodella Pfeffer, 1889 was also established as a genus of a modern hexacoralline anemone based on a single species, B. georgiana Pfeffer, 1889, but has since been reassigned to the genus Parantheopsis McMurrich, 1904 by Carlgren (1949) along with several other species of anenome.

In a series of recent papers, colleagues and I (Milner, 1994; Carroll, 1998; Anderson, 2002, 2003a, 2003b; Anderson et al., 2003) have revised Aïstopoda, a collection of elongate, limbless tetrapods from the Paleozoic of Euramerica. Aïstopods are part of a larger, monophyletic assemblage of tetrapods known as lepospondyls, which are proving to be critical to understanding the early evolution of amniotes and are possibly related to the origins of some, or all, modern amphibians (Carroll, 1995, 2000a, 2000b; Laurin and Reisz, 1997, 1999; Laurin, 1998; Anderson, 2001; Ruta et al., 2003; Vallin and Laurin, 2004).

Until recently considered a rare Appalachian Basin endemic, Pennoceras Miller and Unklesbay, 1942 has emerged as one of the most widespread and locally abundant ammonoids in the lower Missourian of the Midcontinent (Boardman et al., 1994). Here we document the first Midcontinent record of the type species of Pennoceras, P. seamani Miller and Unklesbay, 1942, from the Hushpuckney Shale equivalent in southeastern Kansas. Additional, previously undescribed species of Pennoceras from the Exline Limestone and Mound City Shale equivalents in Oklahoma and southeastern Kansas are described as Pennoceras bennisoni new species and Pennoceras heckeli new species. Discovery of these ancestral species provides clarification on the derivation and early history of Pennoceras and provides a possible link to the Desmoinesian Wiedeyoceratidae.

A bivalve fauna from the Permian—Triassic interval of the Dongpan section, Guangxi, South China is described herein. This bivalve fauna includes 16 species belonging to 10 genera. New taxa are Euchondria fusuiensis, Palaeoneilo qinzhouensis, and Claraia liuqiaoensis. Bed 12 of the interval (Talung Formation) contains the typical late Late Permian ammonoids: Huananoceras sp., Laibinoceras cf. L. compressum Yang, and Qiangjiangoceras sp. Bed 13 (Luolou Formation) contains typical Early Triassic bivalves Claraia dieneri Nakazawa, C. cf. C. wangi (Patte), and C. griesbachi (Bittner), which coexist with the earliest Triassic ammonoid Ophiceras sp. The bivalve and ammonoid distributions at the Dongpan section indicate that bed 12 should be assigned to the Late Permian, and bed 13 should be assigned to the Early Triassic. From the early Changhsingian to the Induan, the byssal notches of Claraia species tend to become progressively narrower, and change from being ventrally extended to being horizontally extended. The species level diversity of Claraia also increases through this interval.

Two specimens of the cornute Phyllocystis crassimarginata Thoral, 1935 from the Lower Ordovician of Southern Montagne Noire (Languedoc, France) showing abnormal numbers of marginal plates are described. the first one (UM 310) is characterized by the insertion of one extra plate between the fourth right marginal and the zygal plate Z. Comparison with a new, undescribed Tremadoc boot-shaped cornute suggests that 1) the extra plate of UM 310 is equivalent to M4, and 2) the three right marginals located between M1 and Z in “normal” specimens of Phyllocystis can be identified as M2, Mc, and M3. Plate configurations of the right thecal margin are thus identical in “normal” Phyllocystis, chauvelicystids, and cothurnocystids. This result indicates that Phyllocystis is probably more closely related to these two clades than to scotiaecystids. Consequently, the identification of the four marginals forming the left thecal margin of Phyllocystis (M′2, M′3, M′5, and M′5) is deduced from a comparison with the cothurnocystid plate pattern. the second abnormal specimen of P. crassimarginata (R64546) is characterized by the loss of M′3. It confirms that reduction in the number of marginals is a general trend in boot-shaped cornutes.

Two new insect-related ichnogenera are reported in fossil dinosaur bones from Upper Cretaceous continental strata in Madagascar and Utah. Cubiculum ornatus n. igen. and isp. is described from numerous fossil bones in the Upper Cretaceous Maevarano Formation of northwestern Madagascar, and consists of hollow, ovoid chambers with concave flanks excavated into both spongy and compact bone. Traces similar in morphology to Cubiculum ornatus have been reported elsewhere in North America, Asia, Europe, and Africa in bones ranging in age from Jurassic to Pleistocene, and have been interpreted as pupal chambers constructed by carrion beetle larvae. Osteocallis mandibulus n. igen. and isp. is described in dinosaur bones from continental deposits of the Upper Cretaceous Maevarano Formation of Madagascar and the Upper Cretaceous Kaiparowits Formation of southern Utah. O. mandibulus consists of shallow, meandering surface trails, composed of numerous arcuate grooves, bored into compact (cortical) bone surfaces, and is tentatively interpreted as a feeding trace. Based on similar patterns of bioglyph preserved in both Cubiculum ornatus and Osteocallis mandibulus, the tracemaker is interpreted to be the same or similar for both borings. Given the recurrent association with animal remains, the tracemaker is furthermore presumed to be a necrophagous or osteophagous insect that used bone as a substrate for both reproduction (C. ornatus) and feeding (O. mandibulus).

A comprehensive treatment of Ordovician crinoids from southwestern Europe is presented, including taxa based on articulated crowns and stems. This summary incorporates new material, new localities, and a revision of some southwestern Europe occurrences. The first record of an Ordovician crinoid from Portugal, Delgadocrinus oportovinum n. gen. and sp., is reported, and this is the oldest known crinoid from the Iberian Peninsula (Arenigian/Oretanian boundary, early Darriwilian). Geographic and temporal ranges of several crinoids are revised from peri-Gondwanan areas in southwestern Europe and northern Africa or modified with new Iberian material. The Spanish range of Heviacrinus melendezi Gil Cid et al., 1996 is extended down into the lower upper Oretanian, and Merocrinus millanae Ausich et al., 2002 is restricted to the upper lower Dobrotivian. The stratigraphic position of Ortsaecrinus cocae Gil Cid et al., 1999b is restricted to the early middle Berounian, and the range of Visocrinus castelli Ausich et al., 2002 is restricted to the late middle Berounian (see Fig. 2). New topotype material of Morenacrinus silvani Ausich et al., 2002 is reported that furthers understanding of the occurrence this taxon, which was previously only positively known from the holotype.

The ornithischia and its sister group, the Saurischia, comprise the Dinosauria. Ornithischians (Weishampel, 2004) are a diverse group of primarily quadrupedal herbivores that include such familiar dinosaurs as the armored stegosaurs and ankylosaurs (Thyreophora), as well as the duckbilled hadrosaurs, pachycephalosaurs, and ceratopsians (Cerapoda). the Ceratopsia (You and Dodson, 2004) includes a number of relatively small basal forms such as psittacosaurs and Neoceratopsia, which comprises protoceratopsids and the larger, more derived horned Ceratopsidae.

New species of ostracods are described from the Tremadoc of the Cordillera Oriental (Argentina). These are among the earliest well-documented records of Ostracoda sensu stricto. The ostracod assemblages are sourced from shallow marine clastics and are dominated by palaeocopes (Eopilla waisfeldae n. sp., Nanopsis coquena n. sp.), and the binodicope Kimsella luciae n. gen. and sp. Eopilla and Kimsella show affinities with species from paleocontinental Gondwana (e.g., Ibero-Armorica, Turkey, Australia, Carnic Alps), but Nanopsis is previously known only from paleocontinental Baltica. This study confirms that two of the major clades of Ordovician ostracods, namely the Binodicopa and the Palaeocopa, were already geographically widespread during the late Tremadoc, suggesting a still earlier origin for these groups, possibly from within the Cambrian to Early Ordovician Bradoriida. Evidence from soft-part anatomy indicates that phosphatocopids, the other group hypothesized to be ancestral ostracods, have apomorphies that preclude them as direct ancestors. The origin of ostracods is more likely to be found within the Bradoriida, a probable polyphyletic group that resembles Early Ordovician ostracods in the external sculpture of their bivalved carapace. Evidence from carapace morphology suggests that the ancestors of true ostracods might lie within the bradoriid groups Beyrichonidae and Hipponicharionidae, a hypothesis that can only truly be tested when more evidence from fossilized soft tissues becomes available.

Crinoids flourished during the Early Mississippian, with late Osagean crinoids being among the most diverse and well studied. Among others, late Osagean crinoid faunas include the well-known Crawfordsville and Indian Creek localities in Montgomery County, Indiana (Van Sant and Lane, 1964; Lane, 1973), and the Keokuk Limestone in the Mississippi River valley stratotype region. the late Osagean faunas in North America have been comprehensively revised recently in a series of studies (Ausich and Kammer, 1990, 1991a, 1991b, 1992; Ausich and Meyer, 1992; Kammer and Ausich, 1992, 1993, 1994, 1996; Ausich et al., 1997, 2000; Meyer and Ausich, 1997).

Sawfishes of the family Pristidae comprise a group of rays having dorsoventrally flattened, sharklike bodies and elongated rostra bearing a row of teeth on each side. Some species may attain total body lengths (TL) of 7 m or more (Compagno and Last, 1999). Unlike the similarly-shaped sawsharks of the family Pristiophoridae, the number of rostral teeth and their proportions are established in utero and maintained into adulthood (Slaughter and Springer, 1968; Miller, 1974), and if a tooth is lost the alveolus remains empty. In addition, the gills are located on the underside of the body and there are no rostral barbels (Tricas et al., 1997; Compagno and Last, 1999). Recent Pristidae consists of five to seven species (depending on synonymy) within two genera, Pristis (Linck, 1790) and Anoxypristis (White and Moy-Thomas, 1941).

Spectacular exposures of large, upright, vase- to barrel-shaped, late Pleistocene sponges are dramatically exposed as part of the Miami Limestone along margins of the C-100C Canal in east-central Miami-Dade County, southeastern Florida. the discovery of this sponge reef by K. J. Cunningham was made in 2004, during a routine drive across the bridge above the C-100C Canal on S.W. 97th Avenue in Miami-Dade County, southeastern Florida. A second location, where comparable sponges are exposed in walls of a burrow lake, was also discovered by K. J. Cunningham in 2004 upon visiting the site after personal communication with L. Noblick, Montgomery Botanical Center, and S. Zona, Fairchild Tropical Botanic Garden, about similarly shaped geologic structures. Subsequently, the C-100C Canal location was documented and some of the sponges were collected and thin sections and samples were sent to J. K. Rigby for examination and evaluation. This paper, on the description and possible taxonomy of the sponges, is a result of that joint effort.

Fossil dinoflagellates, when asymmetrical, almost always have features such as antapical horns on the right side reduced relative to features on the left side. A new species here described, Wilsonidium pechoricum, is therefore unusual in having a reduced left antapical horn. W. pechoricum seems to have originated in the northern Tethys in the latest Paleocene. It subsequently spread northwards and became widely distributed in the Peri-Tethys and parts of the Arctic region during the short interval known as the Initial Eocene Thermal Maximum (IETM). The new species was probably favored by extraordinary paleoecological conditions (high sea-surface temperatures and probably also high nutrient levels) prevailing in neritic waters of the IETM; a time during which aberrant morphotypes were also recorded among other planktonic protists. The apparent absence of W. pechoricum from the North Atlantic region suggests that the Turgay Strait may have functioned as a waterway between the Arctic and Peri-Tethys during the IETM. W. pechoricum is the oldest species of the genus Wilsonidium and possibly descended from the genus Apectodinium. Its early appearance points to a Late Paleocene radiation of the Wetzelielloideae before the well-known Early Eocene radiation in the subfamily, and its morphology is in accordance with a monophyletic origin of the group.

The cycloids represent an enigmatic arthropod group of probably crustacean affinity, occurring mostly in the younger Paleozoic, from the early Carboniferous up to the Late Triassic (Schram et al., 1997). Superficially, cycloids strikingly resemble crabs and were thought to have had a similar lifestyle, becoming extinct when crabs started to radiate. Recently, the existence of a Late Cretaceous cycloid, Maastrichtiocaris rostratus Fraaije et al., 2003, from the Maastrichtian of the Netherlands, proved that cycloids did not go extinct at the end of the Triassic as believed for a long time, but survived much longer, co-occurring with crabs. Due to obvious collecting bias and the incompleteness of the fossil record of arthropods with relatively delicate carapaces in general, neither Jurassic nor Early Cretaceous representatives have been reported hitherto. However, from the Lower Jurassic Posidonienschiefer (‘Posidonia Shale’) of southwestern Germany—famous for its excellent fossil preservation, not only of marine vertebrates and large crinoids living on driftwood, but also many other invertebrate groups (Riegraf et al., 1984; Urlichs et al., 1994)—now a single specimen of a cycloid is recorded and described herein. Although this record helps link the bias between the Triassic and the Late Cretaceous occurrences, the characters of the specimen differ strongly from those of other cycloids, thus requiring the erection of a new genus and species.

Fossils from the Emigrant Formation of Nevada are rare despite the geologic time (uppermost Lower Cambrian to Lower Ordovician) represented by the 700 m thick sequence of deeper water, fine-grained clastics and carbonates. This report documents trilobites from the Elvinia Biozone from this formation in the Goldfield Hills, Nevada. Previously, trilobites and inarticulate brachiopods from the Emigrant Formation have been reported from the lowermost and uppermost portions. in the lower portion, trilobites from the Olenellus Biozone (Dyeran Stage, “Lower” Cambrian) occur in the basal few meters, and are overlain by 15 m of mudstones containing the Eokochaspis nodosa, Amecephalus arrojosensis, and Oryctocephalus indicus biozones (Lin and Knox, 2001; Sundberg and McCollum, 2003) of the lower Delamaran Stage (“Middle” Cambrian, Fig. 1). Collections above the lower mudstones include the Glossopleura Biozone of the Delamaran Stage, Ehmaniella? Biozone of the Topazan Stage, and the Ptychagnostus atavus and Cedaria selwyni biozones of the Marjuman Stage (unpublished data). the only other fossil remains that have been reported include a possible Elvinia Biozone fossil from the middle portion of the formation (McCollum and Sundberg, 2000) and Saukia Biozone fossils from the upper portion of the formation (Albers and Stewart, 1972; unpublished data). Lower Ordovician conodonts have also been found in the upper portion of the formation (M. Miller, personal commun. to L. McCollum, 2003).